A multimedia broadcast multicast system (MBMS) includes a point-to-multipoint (PMP) interface specification for existing and upcoming Third Generation Partnership Project (3GPP) cellular networks. MBMSs are designed to provide efficient delivery of broadcast and multicast services, both within a cell as well as within a core network. For broadcast transmission across multiple cells, it defines transmission via single-frequency network configurations.
Typically, a MBMS is used for delivering real time content, such as audio and/or video, to a large number of user equipment (UEs) at the same time. A MBMS could also be used to deliver file content, such as a mobile software upgrade, to a large number of UEs at the same time. Such file content delivery requires data integrity and any packet loss of the file content by a particular UE needs to be retransmitted back to the particular UE.
One method used by UEs to retrieve lost packets of delivered file content (i.e., a file repair) includes requesting the lost packets via unicast transmissions and receiving the lost packets via unicast transmissions. The file content may be delivered using a protocol (e.g., a file delivery over unidirectional transport (FLUTE) protocol) from a network device in a mobile operator network called a broadcast multicast service control (BMSC). A BMSC is designed to handle broadcast delivery of file content to multiple UEs, but is not designed to handle a large number of UEs making file repair requests. If a large number of UEs make file repair requests to the BMSC, the large number of file repair requests may tax the BMSC and could result in a denial of service (DoS) attack on the mobile operator network. Furthermore, the BMSC must store file content until all UEs are finished making the file repair requests.